heartbeat-server.c
// gcc heartbeat-server.c -o heartbeat-server
// indent -npro -kr -i8 -ts8 -sob -l280 -ss -ncs -cp1 *
/* heartbeat-server.c
*
* improved by ztguang, 2015.12.20
*
* Copyright (c) 2000 Sean Walton and Macmillan Publishers. Use may be in
* whole or in part in accordance to the General Public License (GPL).
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*****************************************************************************/
/*** heartbeat-server.c ***/
/*** ***/
/*** Demonstrates how to keep track of the server using a "heartbeat". If ***/
/*** the heartbeat is lost, the connection can be reestablished and the ***/
/*** session resumed. ***/
/*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <errno.h>
#include <fcntl.h>
#include <resolv.h>
#include <signal.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define BUF_SIZE 1024 //默认缓冲区
#define SERVER_PORT 11111 //监听端口
#define SERVER_HOST "127.0.0.1" //服务器IP地址
#define LISTEN_SIZE 10 //监听队列长度
//两个有用的宏定义：检查和赋值并且检测
#define CHK(eval) if(eval < 0){perror("eval"); exit(-1);}
#define CHK2(res, eval) if((res = eval) < 0){perror("eval"); exit(-1);}
int client;
struct sigaction act;
/*---------------------------------------------------------------------
sig_handler - catch and send heartbeat.
---------------------------------------------------------------------*/
void sig_handler(int signum)
{
if (signum == SIGURG) {
char c;
recv(client, &c, sizeof(c), MSG_OOB);
if (c == '?')
/* Are you alive? */
send(client, "Y", 1, MSG_OOB); /* */
} else if (signum == SIGCHLD)
wait(0);
}
/*---------------------------------------------------------------------
servlet - process requests
---------------------------------------------------------------------*/
void servlet(void)
{
int bytes;
char buffer[BUF_SIZE];
bzero(&act, sizeof(act));
act.sa_handler = sig_handler;
act.sa_flags = SA_RESTART;
sigaction(SIGURG, &act, 0); /* connect SIGURG signal */
if (fcntl(client, F_SETOWN, getpid()) != 0)
perror("Can't claim SIGIO and SIGURG");
do {
bzero(buffer, BUF_SIZE);
bytes = recv(client, buffer, sizeof(buffer), 0);
printf("recieve [%s] from client-%d
", buffer, client);
if (bytes > 0)
send(client, buffer, bytes, 0);
} while (bytes > 0);
printf("end while
");
close(client);
exit(0);
}
/*---------------------------------------------------------------------
main - set up client and begin the heartbeat.
---------------------------------------------------------------------*/
int main(int count, char *strings[])
{
bzero(&act, sizeof(act));
act.sa_handler = sig_handler;
act.sa_flags = SA_NOCLDSTOP | SA_RESTART;
if (sigaction(SIGCHLD, &act, 0) != 0)
perror("sigaction()");
int listener; //监听socket
struct sockaddr_in addr, peer;
addr.sin_family = PF_INET;
addr.sin_port = htons(SERVER_PORT);
addr.sin_addr.s_addr = inet_addr(SERVER_HOST);
socklen_t socklen;
socklen = sizeof(struct sockaddr_in);
CHK2(listener, socket(PF_INET, SOCK_STREAM, 0)); //初始化监听socket
// 设置套接字选项避免地址使用错误
int on = 1;
if ((setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))) < 0) {
perror("server: setsockopt failed");
exit(EXIT_FAILURE);
}
CHK(bind(listener, (struct sockaddr *)&addr, sizeof(addr))); //绑定监听socket
//printf("listen
");
CHK(listen(listener, LISTEN_SIZE)); //设置监听
printf("server: listening
");
while (1) {
client = accept(listener, (struct sockaddr *)&peer, &socklen);
printf("accept client-%d
", client);
if (client > 0) {
if (fork() == 0) {
close(listener);
servlet();
} else
close(client);
} else
perror("accept()");
}
close(client);
return 0;
}
heartbeat-client.c
// gcc heartbeat-client.c -o heartbeat-client
// indent -npro -kr -i8 -ts8 -sob -l280 -ss -ncs -cp1 *
/* heartbeat-client.c
*
* improved by ztguang, 2015.12.20
*
* Copyright (c) 2000 Sean Walton and Macmillan Publishers. Use may be in
* whole or in part in accordance to the General Public License (GPL).
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*****************************************************************************/
/*** heartbeat-client.c ***/
/*** ***/
/*** Demonstrates how to keep track of the server using a "heartbeat". If ***/
/*** the heartbeat is lost, the connection can be reestablished and the ***/
/*** session resumed. ***/
/*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <resolv.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define SERVER_PORT 11111 //监听端口
#define SERVER_HOST "127.0.0.1" //服务器IP地址
#define DELAY 2 /*seconds */
//两个有用的宏定义：检查和赋值并且检测
#define CHK(eval) if(eval < 0){perror("eval"); exit(-1);}
#define CHK2(res, eval) if((res = eval) < 0){perror("eval"); exit(-1);}
int serverfd, got_reply = 1;
/*---------------------------------------------------------------------
sig_handler - if the single is OOB, set flag. If ALARM, send heartbeat.
---------------------------------------------------------------------*/
void sig_handler(int signum)
{
int bytes, len;
struct tcp_info info;
int leng = sizeof(info);
if (signum == SIGURG) {
//*
getsockopt(serverfd, IPPROTO_TCP, TCP_INFO, &info, (socklen_t *) &leng);
if ((info.tcpi_state == TCP_ESTABLISHED)) { // socket connected
; //return 1;
} else { // socket disconnected
return;
}
//*/
char c;
CHK2(bytes, recv(serverfd, &c, sizeof(c), MSG_OOB));
if (bytes == 0) return;
got_reply = (c == 'Y'); /* Got reply */
fprintf(stderr, "[server is alive]
");
} else if (signum == SIGALRM) {
printf("reply = %d
", got_reply);
if (got_reply) {
alarm(DELAY); // Wait a while
//*
getsockopt(serverfd, IPPROTO_TCP, TCP_INFO, &info, (socklen_t *) &leng);
if ((info.tcpi_state == TCP_ESTABLISHED)) { // socket connected
; //return 1;
} else { // socket disconnected
return;
}
//*/
CHK2(len, send(serverfd, "?", 1, MSG_OOB)); // Alive??
if (len == 0) return;
got_reply = 0;
} else {
fprintf(stderr, "Lost connection to server!
");
alarm(DELAY); /* Wait a while */
}
}
}
/*---------------------------------------------------------------------
main - set up client and begin the heartbeat.
---------------------------------------------------------------------*/
int main(int count, char *strings[])
{
int bytes, len;
char line[100];
struct tcp_info info;
int leng = sizeof(info);
struct sigaction act;
bzero(&act, sizeof(act));
act.sa_handler = sig_handler;
act.sa_flags = SA_RESTART;
sigaction(SIGURG, &act, 0);
sigaction(SIGALRM, &act, 0);
struct sockaddr_in seraddr;
seraddr.sin_family = PF_INET;
seraddr.sin_port = htons(SERVER_PORT);
seraddr.sin_addr.s_addr = inet_addr(SERVER_HOST);
CHK2(serverfd, socket(PF_INET, SOCK_STREAM, 0));
if (fcntl(serverfd, F_SETOWN, getpid()) != 0) // claim SIGIO/SIGURG signals
perror("Can't claim SIGURG and SIGIO");
while (1)
{
got_reply = 1;
close(serverfd);
CHK2(serverfd, socket(PF_INET, SOCK_STREAM, 0));
if (fcntl(serverfd, F_SETOWN, getpid()) != 0) { // claim SIGIO/SIGURG signals
perror("Can't claim SIGURG and SIGIO");
continue;
}
if (connect(serverfd, (struct sockaddr *)&seraddr, sizeof(seraddr)) == 0) {
printf("connect [OK]
");
alarm(DELAY);
do {
//*
getsockopt(serverfd, IPPROTO_TCP, TCP_INFO, &info, (socklen_t *) &leng);
if ((info.tcpi_state == TCP_ESTABLISHED)) { // socket connected
; //return 1;
} else { // socket disconnected
break;
}
//*/
//CHK2(len, send(serverfd, "?", 1, MSG_OOB)); // Alive??
//got_reply = 0;
//CHK2(len, send(serverfd, "restart", 7, 0));
//printf("send [restart]
");
memset(line, 0x00, 100);
gets(line);
printf("send [%s]
", line);
//CHK2(len, send(serverfd, "adsf", 4, 0)); sleep(1);
CHK2(len, send(serverfd, line, strlen(line), 0)); // send
if (len <= 0) break;
CHK2(bytes, recv(serverfd, line, sizeof(line), 0)); // recieve
if (bytes <= 0) break;
} while (bytes > 0);
printf("end while
");
} else {
perror("connect failed, retry!
");
sleep(2);
}
}
//close(serverfd);
//return 0;
}